The RA is an autoimmune disease of unknown etiology that affects approximately 1% of world's population. It is a syndrome characterized by chronic inflammation of the joints, although systemic manifestations can be also observed. This illness begins with the inflammation of the synovial membrane and frequently causes the erosive destruction of the adjacent cartilage and the bone, which result in moderate physical inability of 80% of the patients and an early mortality (Moctezuma, J. F. (2002) Manifestaciones articulares de la Artritis Reumatide. Revista Mexicana de Reumatología 17:211-219). RA can be presented at any age, without distinctions of races or ethnic groups, but the maximum incidence of its beginning happens between 25 and 55 years old. Among people with RA, the women overcome the men in a proportion from three to one (Emery, P. (2002) Early referral recommendation for newly diagnosed rheumatoid arthritis: evidence based development of to clinical guide. Ann Rheum Dis. 61:290-297).
The cause of RA is unknown. It is an illness that involves the presence of genetic, environmental, immunological and hormonal factors. Certain genes have a role in the immune system, associated with a tendency to develop RA. At the same time, some people with RA don't have these genes and other people having them never develop the illness. Therefore, it has been suggested that the genetic background is important but it is not decisive.
In models of autoimmune disease, microbial antigens with similar structure to own antigens can release a crossed response to autoantigens, producing an alteration in the mechanisms of tolerance and perpetuating an autoimmune response. In general sense, the damage and local necrosis in a tissue produced by an infectious agent could discover the autoantigen cryptic epitope, being able to activate autoreactivate T cells (Albert, L. J. (1999) Mechanisms of Disease: Molecular Mimicry and autoimmunity. N Engl J Med 341:2068-2074)
The phase of transition of T lymphocyte between tolerance and immunity/autoimmunity is regulated at different levels. Two important parameters in this transition are the state of maturation of the Antigen Presenting Cells (abbreviated APC) and the levels of autoantigens that are detected by the immune system (Ohashi, P. S. (2002) Making and breaking tolerance. Current Opinion in Immunology 14:744-759).
One of the current hypotheses that tries to explain the development of autoimmune diseases, outlines that APC in absence of signs of the innate immune system or of signs of danger, remain relatively immature and induce tolerance in autoreactive T cells, when own peptides are presented to them (Steiman, R. M. (2000) The induction of tolerance by dendritic cells that have captured apoptotic cells. J Exp Med. 191:411-416). The induction of peripheral tolerance is also correlated with the concentration of own antigen (Kurts, C. (1999) CD8 T cell ignorance or tolerance to islet antigens depends on antigen dose. PNAS 96:12703-12707). An increment in the presentation of own antigens due to the increment of their expression levels, allows their detection by autoreactive ignorant T cells. If levels of own antigens are increased in absence of events that promote the maturation of APC, the tolerance to these antigens is maintained, otherwise, it happens in presence of proinflammatory signs or other events that promote the maturation of the APC, the tolerance is breaks by activation of the ignorant T cells and autoimmune diseases are developed (Janeway, C. A. (2002) Innate immune recognition. Annu Rev Immunol. 20:197-216). The infectious agents that have been object of study like cause of RA are: Epstein Bar virus, the retrovirus, virus of the hepatitis C, the Mycobacterium tuberculosis (abbreviated Mt) and the Helicobacter pylori, among others.
The pathogenesis of RA is characterized by the concerted action of different types of cells that cause the progressive destruction of the cartilage and the bone.
In normal situations a balance exists among the inflammatory cytokine as: TNFα, IL-1, IL-6, IL-15, IL-16, IL-17, IL-18 and the IFNγ, and the anti-inflammatory ones as IL-4, IL-11, IL-13 and antagonistic of IL-1 or TNFα. In the RA this balance moves however in favor of the inflammatory cytokines (Arend, W. P. (2001) Cytokine imbalance in the pathogenesis of rheumatoid arthritis: The role of interleukin-1 receiving antagonist. Semin Arthritis Rheum 30(2):1-6)
The recognition of an exogenous antigen or autoantigen is probably the reason of a series of events that cause destruction of the joints in patients with RA. This phenomenon cause the activation of T CD4+ lymphocytes that in cooperation with the stimulation of different cytokines, induces their differentiation to cells Th1 with the consequent liberation of proinflammatory cytokines (IL-2 and INFγ) (Simón, A. J. (2001) Biological therapy in Rheumatoid Arthritis. Magazine of Clinical Investigation 53(5):452-459). Many investigators coincide that the chronic inflammation of the joints is induced by these activated T cells that infiltrate the synovial membrane. The action of these cytokines on macrophages causes the production of high amount of TNFα and IL-1. These cause a series of local and systemic actions as regulating the expression of the molecules of adhesion in the endothelial cells (LFA1, ICAM-1), which recruit other cells to the inflammation sites. They also stimulate macrophages, fibroblasts, condrocytes and osteoclasts to the liberation of others mediators of the inflammation, as IL-15 and IL-8. TNFα and IL-1 stimulate the proliferation of the synovial membrane that causes formation of pannus, they can also induce the differentiation of B lymphocytes to cells producing antibodies that potentially participate in the destruction of the joint. They also inhibit the production of anti-inflammatory cytokines (IL-4 and IL-14) produced by Th2 cells and stimulate hepatocytes to liberate IL-6. IL-6 favors the production of the proteins of the acute phase, which participate strengthening the immune response (Forre, O. (2000) New possibilities of treatment in AR. Scand J Rheumatol 29(2):73-84).
Among autoantigens involved in the pathogenesis of RA is Hsp60, a protein that belongs to the family of the Hsp, which are immunogenic proteins with exceptionally evolutionary conservation. The immune response against the strange Hsp is an important mechanism of defense against bacterial infections. The antibodies against these proteins can be abundant in healthy people and in patient with autoimmune illnesses and they can cross react with the own antigens (Chen, W. (1999) Human 60-kDa Heat-Shock Protein: To Danger Signal to the Innate Immune System. J. Immunol. 162:3212-3219).
The Hsp65 of Mt is homologous to the Hsp60 of the mammals. This suggests that the Hsp60 can be recognized as autoantigen in patient with RA. Comparing patients with osteoarthritis and patients with RA, these last ones have an increase of prolipherative response of B lymphocytes in the synovial liquid to the Hsp65 of mycobacterium. The intensity of the response correlates with the synovial inflammation. This response is not specific for RA compared with other inflammatory illnesses (Life, P. (1993) Responses to Gram negative enteric bacterial antigens by synovial T cells from patients with juvenile chronic arthritis: recognition of heat shock protein hsp60. J. Rheumatol. 20:1388-1396).
The concentration of Hsp is a possible sign of danger for the immune system, which are released from dead cells, and can induce an inflammatory response and to begin the maturation of the APC. The Hsp, are intracellular proteins, which are not expressed in the cellular membrane, neither are secreted, so that the Hsp are attractive candidates for molecules that constitute signs of danger (Van den Berg, WB. (1998): Joint inflammation and cartilage destruction may occur uncoupled. Springer Semin Immunopathol. 20:149-164).
Several preparations have been proposed using the Hsp60 or its derived peptides for the treatment of some autoimmune pathologies. For example in the patent EPO262710, the use of several peptides of the Hsp60 of Mt is proposed for the treatment and diagnosis of autoimmune illnesses, especially of arthritic conditions. This invention is based on the fact that previous infections with several bacteria can trigger the development of autoimmune illnesses, in genetically susceptible people, for example: patients with RA can show a high reactivity to microbial antigens.
These same inventors in the patent EPO322990 propose the use of others peptides of the Hsp60 of Mt with the same purpose of the previous patent.
In the patent application W09610039 they intend the use of a peptide of the Hsp60 of Mt for the diagnosis and treatment of autoimmune arthritis.
In the patent application WO9711966, the authors intend the use of peptides of non conserved regions of the hHsp60, that don't coincide with the Hsp60 of bacteria that could induce tolerance in T cells of patients with RA.
The patent application WO0143691 proposes the use of pharmaceutical preparations composed specifically by peptides of the hHsp60 and their variants for the prevention of inflammatory illnesses such as RA.
In the U.S. Pat. No. 6,180,103 the authors intend the use of a peptide of the Hsp60 called p277 and its analogous for the diagnosis and prevention of the diabetes type I.
The U.S. Pat. No. 5,993,803 protects the use of the Hsp60, the peptide p277 and a group of derived peptides of this protein to reduce the severity of the immune response during the transplant of organs.
Recently it has been considered that the atherosclerosis presents a series of similar characteristics to autoimmune processes. In the patent application WO0072023 the authors purpose a method for the treatment and diagnosis of the atherosclerosis and coronary illnesses using a preparation that contains the protein Hsp60.
In the patent application WO02057795, a new method is protected for the diagnosis and treatment of the osteoporosis using proteins of the family of Hsp and proteins from pathogens such as: viruses and bacteria.
At the present time, cure doesn't exist for the RA. The current methods of treatment are centered in alleviating the pain, to reduce the inflammation, to retard the damages of the joints and to improve the functions and the well-being of the patients. Recently immunomodulating medications have been elaborated, that blocks cytokines that participate in the beginning and maintenance of the inflammatory response in RA, with the purpose to stop or slow the progression of the illness. For this kind of therapy two types of medications exist: blocking the action of the Tumor Necrosis Factor (abbreviated TNFα) and those that inhibit the action of the interleukin 1 (IL-1).
Although the results are promissory with the therapies anti-TNFα and anti-IL-1, the percentage of infections is high. Many of treated patients with these drugs develop serious infections that are fatal in some cases; including other autoimmune illnesses, neoplasias, etc. Besides, they are very expensive medications (Breshinan, B. (1998) Treatment of rheumatoid arthritis with recombinant human anti-interleukin-1 antagonist. Arthritis Reum. 41:2196-2204)
Oral tolerance has been proposed as a method of creating peripheral tolerance in front of certain antigens. This can be induced by mechanisms of active suppression, anergy or clonal deletion, depending on the doses and the frequency of the administration of the antigen. The method can induce regulatory T cells that are activated in a specific way by the antigen, but exert its action independently (active suppression). For the regulatory action takes place, it is not necessary to administer the supposedly pathogenic antigen, but any other able to induce the active suppression in the inflammatory focus, inhibiting the activity of the pathogenic effector cells. Collagen type II (abbreviated CII) is the autoantigen that has been used more frequently in this sense. The results of the studies carried out in patients with RA, using chicken and bovine CII have given contradictory results (Trentham, D. E. (1993) Effects of oral administration of type II collagen in rheumatoid arthritis. Science 261:1727-1730; Sieper, J. (1996) Oral type II collagen treatment in early rheumatoid arthritis: to double-blind, placebo-controlled, randomize trial. Arthritis Rheum. 39:41-51).
The U.S. Pat. No. 6,153,200 intends the use of a peptide of the Hsp70, protein belonging to the family of Hsp, to induce tolerance for oral route in patients with RA.
Another variant that has been suggested to induce tolerance is through APL peptides, based on the fact that T cells are activated if the specific T CD4+ lymphocytes for a certain antigenic peptide recognize the antigen presented by competent APC. Nevertheless, if the same T cell is first activated with a different form from the antigen, in which one of the contact sites with the TcR are lightly altered, it can result in a partial activation or even inactivation of the T cells. These antigens are named APLs. The APLs are similar to immunogenic peptides with one or several substitutions in the essential positions of contact with the TcR or with MHC that interfere the cascade of necessary events for the complete activation of the T cells.
Conceptually, APLs can be designed with similar properties to the immunogenic peptide (agonist) among other effects for increasing the response of T cells toward specific antigens. This effect is advantageous under pathological conditions as infectious illnesses. Peptides can also be designed with antagonistic properties to the immunogenic peptide that could be beneficial in the control of autoimmune illnesses since they can block the response of T cells acting as antagonistic of the TcR (M. De Magistris (1992) Antigen analog-major complex histocompatibility complexes act as antagonist of the T cell receptor. Cell 68:625-634), partial agonist or inducing a population of regulatory T cells that mediate the active suppression (Evavold, B. D. (1991) Separation of IL-4 production from Th cell proliferation by an altered T cell ligand. Science 252:1308-1310). The capacity to experimentally manipulate the intrinsic properties of peptide ligands allows altering the nature, the course and the power of the immune cellular response appropriately.
Up to this moment, two clinical trials in humans using type APL peptides have been performed for the treatment of autoimmune diseases. In both assays, the peptides are derived from an epitope in position 83 to 93 of the myelin basic protein. One of these trials included 142 patients with multiple sclerosis, and it was suspended because 9% of the patients developed hypersensitivity (Ludwig Kapposi (2000) Induction of non-encephalitogenic type 2 T helper-cell autoimmune response in multiple sclerosis after administration of an altered peptide ligand in to placebo controlled, randomized phase II trial. Nature Medicine 10:1176-1182).
The other trial included 25 patients and was also interrupted, because in three patients was observed an exacerbation of the illness (Bibiana Bielekova (2000) Encephalitogenic potential of the myelin basic protein peptide (amino acids 83-99) in multiple sclerosis: Results of to phase II clinical trial with an altered peptide ligand. Nature Medicine 6:1167-1175). The main author of this work analyzes the possible factors that determined these negative results, and outlines that the changes carried out in the APL's sites may originate new motifs of union to the HLA (like it happened in the case of the APL binding to DRB1*0404 present in patient I), the complex APL-HLA can also stimulate T cells not eliminated in the negative selection that can be cross-activated by the native autoantigen. In this trial high concentrations of the APL were used in the pharmaceutical preparations, which can stimulate T cells with high similarity for the autoantigen and to induce a heteroclitic T cells response. (Bibiana Bielekova and Roland Martin (2001) Antigen-specific immunomodulation via altered peptide tying. J Mol Med. 79:552-556).
For carrying out these two clinical trials, the authors didn't previously analyze the in vitro response of the T cells from the patients to the APL. They also did not consider the types of HLA molecules expressed by the treated patients
The main challenge in the treatment of the autoimmune diseases is the development of therapeutic strategies that can eliminate pathogenic T cells with specificity, without affecting other non related T cells. Therefore, therapeutic search should find a secure, specific and effective way of turning off an advanced autoimmune process.
The present invention, in contrast to the state of the previous technique, proposes the use of peptides of the hHsp60 and its derived type APL, which induce inhibitory molecular mechanisms, in a specific way, of the course of RA.